var defaultVShader = 
"uniform mat4 u_modelViewProjMatrix;"+
"uniform mat4 u_normalMatrix;"+
"uniform vec3 lightDir;"+

"attribute vec3 vNormal;"+
"attribute vec4 vPosition;"+

"varying float v_Dot;"+

"void main()"+
"{"+
"	gl_Position = u_modelViewProjMatrix * vPosition;"+
"	vec4 transNormal = u_normalMatrix * vec4(vNormal, 1);"+
"	v_Dot = max(dot(transNormal.xyz, lightDir), 0.0);"+
"}";